I'm having some trouble with system stability when tethering USB devices to my computer. When I try to copy a large file (around 150-650 MB) from a SD Card, the computer would completely freeze after copying some portion of the file. The same stability issue occurs when I try to download and install packages with Synaptic and when downloading and installing updates with MintUpdate while using my mobile phone as a modem, which is connected via USB. I've been trying to troubleshoot this issue but can't tell what to do, due to my lack of familiarity with Linux. Could anyone help me with this? I mean, where to start? Does Mint (Elyssa) keep a comprehensive record of system activity that I can use to know what the culprit is?

I've entered all the commands you told me and read through all the available logs but still have no idea on what's wrong. Are there any particular strings that I have to look for? Everything seems pretty standard to me, nothing unusual.

It seems the common factor is (large?) files through USB

But not the only factor. Using my phone as a modem through USB also causes random freeze, albeit less frequently.

It's been a while now since my last reply and I want to report that this stability issue no longer occurs. The thing is, I'm not sure what actually caused the problem to go away. I applied your solution on the other thread that you pointed me to, and it seemed to improve system stability by quite a bit although not entirely getting rid of the problem. I then made the mainboard's sensors work under Mint (it didn't work out of the box) and now I no longer have any kind of annoying random freeze any more. Thus, I think the solution you gave me plus functional mainboard sensors under Mint have sorted out the stability issue for me. But well, that's simply a wild guess at best unless somebody could say otherwise.